TELKOMNIKA
, Vol.10, No.2, June 2012, pp. 229~234 ISSN: 1693-6930
accredited by DGHE DIKTI, Decree No: 51DiktiKep2010 229
Received February 17, 2012; Revised April 17, 2012; Accepted April 26, 2012
Overcoming Challenges of Renewable Energy on Future Smart Grid
J.O. Petinrin , M. Shaaban
Centre of Electrical Energy System CEES, Faculty of Electrical Engineering, Universiti Teknologi, Malaysia
e-mail: wolepet01yahoo.com , m.shaabanfke.utm.my
Abstrak
Peningkatan kompleksitas dari grid konvensional terkait pertumbuhan penduduk, kemajuan teknologi, dan infrastruktur adalah faktor-faktor yang berkontribusi sangat besar terhadap ketidakstabilan,
ketidakamanan, dan ketidakefisienan penggunaan energi listrik. Untuk mengatasi masalah ini, keberlanjutan energi lingkungan memerlukan penggunaan energi terbarukan untuk keberlanjutan pasokan
listrik. Intermitansi dan fluktuasi dari energi terbarukan merupakan tantangan besar pada grid cerdas. Makalah ini mengungkapkan tantangan potensi energi terbarukan pada grid cerdas dan menawarkan
solusi dengan penerapan DC tegangan tinggi HVDC dan piranti sistem transmisi fleksibel AC FACTS. Fungsi dan keuntungan dari piranti FACTS disajikan dalam makalah ini. Kendali tegangan dan stabilitas
dengan aplikasi FACTS juga dibahas karena FACTS memiliki pengendalian cepat dan kemampuan untuk bertukar daya aktif dan reaktif secara independen.
Kata kunci:
intermiten, kekuasaan stabilitas, energi terbarukan, stabilitas tegangan
Abstract
The increasing complexity of the conventional grid due to population growth, advancement in technology, and infrastructures are the factors that contribute immensely to instability, insecurity, and
inefficiency of the use of electrical energy. To overcome the problems, the environmental energy sustainability calls for the use of renewable energy for sustainability of power supply. Intermittency and
fluctuation of the renewable energy is a great challenge on the smart grid. This paper reveal the potential challenges of renewable energy on the smart grid and proffer solution with the application of high voltage
DC HVDC and Flexible AC transmission system FACTS devices. The functions and advantages of FACTS devices are presented in this paper. Voltage control and stability control with FACTS application
are also discussed because FACTS has fast controllability and capability to exchange active and reactive power independently.
Keywords : intermittent, power stability, renewable energy, voltage stability
1. Introduction
With the new development in power system, the smart grid allows seamless integration of renewable energy sources into the conventional grid. The total amount of economically
extractable from wind is considerably more than the present human power use from all resources [1]. However, with increasing level of renewable energy sources especially wind
power [2] the intermittent and fluctuating features of wind generator increase the uncertainties and challenges for future smart grids [2-3]. There is uncontrollable power flow in the power
system governed by Ohm’s law and Kirchhoff’s law which may cause bottlenecks in the power system such as angle and voltage instability. The angle and voltage instability may result in
generator outages, line tripping and blackouts [4].
In most power generating system, the main source of energy the fuel can be manipulated, but that is not the case of wind and solar energies [5]. Both wind and solar may
not always be available where and when needed [6]. They are not dispatchable like the conventional sources of electrical energy. They both have uncontrollable power output which
results in intermittent generation. Control challenges are part of the key enabling technologies for the integration of renewable energy resources. Most especially, wind and solar plants exhibit
dynamics changes and nonlinearities challenges that require effective use of advance control techniques. This will not only increase their performance, but would increase the number of
operational hours of wind and solar plants and minimize the cost per kilowatt-hour produced.
ISSN: 1693-6930
TELKOMNIKA
Vol. 10, No. 2, June 2012 : 229 – 234 230
The challenges can be overcome with the utilization of innovative technologies like HVDC and FACTS devices which has the ability to cope with the new challenges. HVDC and
FACTS has the characteristics to mitigate technical problems in the smart grid, they increase the transmission capacity and system stability very efficiently and assist in militating cascading
disturbances [7]. HVDC and FACTS can make available both steady state and dynamic control for power system. With the application of HVDC and FACTS devices either of them or
combination of both will result in much more secured and reliable power grid. The devices are equally useful in distributed generation interconnections, voltage and power flow controls of
wind energies and improve the power quality of the system.
Privatization and deregulation are posing lots of challenges on the electrical power system. This makes the grid to be loaded up to its stability limits and wide-area power trading
with quick varying load patterns will add to increasing transmission congestion [8]. There are lots of challenges before the electricity distribution system in responding to the increasing
demand of customer for electricity in the modern world [9]. The more the demand on electricity, the more the likelihood of outages, voltage and frequency violation and other power quality
disturbances. However, more demand on renewable energy, distributed generators and storage devices is driving the conventional grid into what is popularly known as smart grid. Moreover,
increasing numbers of distributed generation, most especially wind generation, integrated with the power grid brings further uncertainty of load and power flow distribution which gives
additional strain to the system [4]. The daily wind production patterns for the month of May 2007 in Tehachapi, Califonia is shown in fig. 1 while fig. 2 shows the load and wind production
for a typical spring day [10]. The variability of the wind energy has a great consequence on the voltage fluctuation at the bus where the wind generator is connected and the load voltage
fluctuation which affects the power system voltage stability. This is a big challenge to the distribution system operator DSO to match demand with energy produced.
Figure 1. Daily output of wind production Figure 2. Comparison of wind generation -May 2007 [10] to load demand [10]
2. Renewable Energy Challenges
